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Tuesday, September 7, 2010

Lunette: Reducing Network Mission Costs

Note: While I'm traveling this month with only occasional short access to the Internet, I'm reading through some of the back log of proposed mission concepts. I'll post short summaries of the more interesting ideas. Unfortunately, I'm unlikely to have time to search down Internet sites to provide hot links to the abstracts and presentations I'm reading. I'll try to provide sufficient information on each that you can easily do a search to find the original documents.

In this post, I'll a mission concept for the Discovery program (~$425M PI cost, ~$800M fully burdened cost) that would explore the moon's interior.

The proposal was described in an extended abstract (2 pages) for this year's 41st Lunar and Planetary Science Conference.

Lunnette: Establishing a lunar geophysical network without nuclear power through a Discovery-class mission
LPSC abstract 2710.pdf

Studies of the interiors of the moon and planets has been repeatedly prioritized by review panels prioritizing future planetary exploration. Planets and large moons have had complex interactions between the formation, evolution, and current state of their interiors and surfaces and, where they exist, their atmospheres. While surfaces and interiors have received considerable attention, interiors have received much less investigation. Gravity measurements from orbiters and flybys provide some information on interiors, but seismic and heatflow measurements are considered essential to extend our knowledge. To date, only the moon has been investigated by a network of surface stations left by the Apollo astronauts. Those instruments represent decade old technologies and were placed at sites chosen for surface geology rather than optimizing the design of the network.

The Lunette proposal attempts to address one of the major roadblocks to establishing surface networks, cost. The current leading proposal for an initial four node lunar network, the International Lunar Network (ILN), reportedly would cost more than a New Frontiers mission (~$650M PI cost, ~$1.2B fully burdened cost). I've seen estimates for a four node Mars network in the range of $1.5B.

The Lunette proposal would minimize costs through three strategies. First it would use solar power in place of nuclear power and would "use new power management technology" to survive and operate through the long lunar night for at least two years of operation. Second, it would place just three nodes on the surface instead of ILN's four. And third, it would depend on international partners to supply and pay for a very broad band seismometer that would be an order of magnitude more sensitive than the Apollo seismometers, a short period seismometer, and a heat flow probe. U.S. scientists would supply a low-frequency electromagenetic sounding instrument and a laser retroreflector.

Editorial thoughts: Studying planetary interiors is important. Two NASA missions in development, the JUNO Jupiter orbiter and the GRAIL lunar orbiters would study the interiors of their bodies using gravity and magnetometer measurements. Studying the interiors of the moon and Mars from the surface is the next logical step. If the Lunette team has found ways to dramatically reduce costs for surface networks, that would be welcome news. The list of authors includes two authors from JPL, suggesting that the engineering analysis may be reasonably advanced. (I don't recognize these author's names and so don't know if they are on the science or engineering side of JPL, and I can't do a web search from the tent I'm writing this in.) On the other hand, the costs of many Discovery proposals reportedly have proven to have under estimated costs in the eyes of the panels that review the proposals. Getting a network mission into even the cost cap of a New Frontiers mission would still be a significant achievement, though. The Lunette proposal sounds like solid progress in that direction.

About Me

You can contact me at futureplanets1@gmail.com with any questions or comments.
I have followed planetary exploration since I opened my newspaper in 1976 and saw the first photo from the surface of Mars. The challenges of conceiving and designing planetary missions has always fascinated me. I don't have any formal tie to NASA or planetary exploration (although I use data from NASA's Earth science missions in my professional work as an ecologist).
Corrections and additions always welcome.